The Open Mobile Alliance (OMA) Secure User Plane Location (SUPL) is an IP-based protocol for location determination of mobile devices (such as mobile phones), known in OMA specifications as SUPL Enabled Terminals, or SETs. OMA SUPL v2.0 introduced the capability to support Emergency SUPL Location Platforms (E-SLPs) interacting with SETs to assist in locating users in emergency situations (e.g., when an emergency call is placed using the SET). Problematically, however, the protocol does not indicate what should happen in the case of an authentication failure during security negotiation in these emergency situations. This can result in delays that can be costly during an emergency.